Method of and apparatus for recovering volatile metallic values, in the form of metallic oxids, from molten slag.



a. WiT'IIEBORG. I v METHOD OF AND APPARATUS FOR RECOVERINGVOLATJLE MTALLl 8.VALUES IN THE FORM OF METALLIC oxms mom mum-sue.

APLICATlON EILED MAR. 6, I917.

PatentedDeo. 18, 1917.

2 SHEETS-SHEET awwmtoz H. WiTTEBORG.

METHOD OF AND APPARATUS FOR RECOVERING VOLAHLE METALLIC VALUES IN THE FORM OF METALLLG OXIDS FROM MOL TEN SLAG.

APPLICATION FILED MAR. 6. m1.

Patented Dec. 18,1917.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

HERMAN WITTEBORG,

METHOD OF AND To all whom,- it may concern:

Be it known that I, HERMAN Wrrrnsone, a citizen of the United States, residin at Caldwell, in the county of Canyon and State of Idaho, have invented certain new and useful Improvements in- Methods of and A paratus for Recovering Volatile Metallic v lues, in the form'of Metallic Oxids, from Molten Slag; and I do herebydeclare the following to be a full, clear, and exact description of the invention, such as will on able others skilled in the art to which it appertains to make and use the same.

This invention relates to the recovery of volatile metallic values, in the form of metallic oxids, from molten slag.

For the sake of brevity, I shall simply employ the terms zinc and zinc oxi s, but it will be understood that I do not limit myself in this regard, as the invention itself is susceptible for use with other volatillzable metals or metallic compounds.

It may be statedat the outset that my. invention is notfor a smelting process for the direct recovery of metals from crushed ores or from broken up bri%uets of slag containing metallic values. I for the recovery of raw metals, as such, by

the sim le volatilization and condensation of di'stil ed vapors, nor even does it broadly reside in the recovery of metallic oxids by the oxidizing of the zinc vapors distilled out of molten slag by treating the same in an externally heated retort containin a large quantity 'of the molten'slag, whet or taken from a blast furnace, or re-smelted after, having been formed into briquets containing 'a suitable flux and reducing agent. Finally, the invention does not specifically rely upon the step of reacting upon the slag, in the form of a molten bath, I by the introduction of a suitable agent for releasing and driving out .the metallic values, all of whichsteps may be broadly disclosed in the prior art.

It is true that itis one of myaims to avoid the necessity of re-smelt n' lump,

granulated orbriqueted slag,-an to this extent I do take the molten slag directly from its source of production. Also, in extracting its metallic values by volatilization,

ipprior to final oxidation, I preferably 'though not necessarily, introduce any of either is. itv

or CALDWELL, IDAHO.

APPARATUS FOR RECOVERING VOLATILE METALLIC VALUES, IN THE FORM OF METALLIC OXIDS, FROM MOLTEN SLAG.

Specification of Letters Patent. Patented Dec, 18, 1917, I Application filed larch 6, 1917. Serial No. 152,729. I

the well known re-acting or reducing agents,

as may be found expedient in practice.

Taken as a whole, however, I attain the desired ends, by additionally treatin the' molten slag in a manner which is be ieved to be more efiicient, in certain of its steps and features, to the methods heretofore employed, the primar object of my invention being .to increase e ciency and output, and

at a substantially reduced expense inpoint of economy of time, attention required and 'cost of operation, all of which are manifestly of major importance.

My invention, therefore, is not merelydirected. to the broad idea of recovering zinc oxids from the va ors of molten slag, but wholly resides in t e novel method and the combined arrangement-and functioning of the elements of the apparatus hereinafterdisclosed, the essential steps and features of which will be succinctly stated in the appended claims, when viewed in the light of the following detailed description and accompanying drawings, forming a part of this application, in which drawings Figure 1, illustrates a practical systematic arrangement of elements for carrying out the improved method, being a view in plan 9f my improved apparatus itself, with certain minor elements omitted.

Fig.2, is a vertical 'sectiOnal view through a pair of communicating units, taken alongthe plane of the line 2-2 of Fig. -1 and showing the addition of a twyer nozzle and bottom container pan and I Fig. 3, is a vertical sectional view taken transversely through a slightly .modified construction of a the application of a jacketed cooling chamber for the bottom of the retort units, if de-.

sired, and also showing the twyer nozzles on the opposite side of the retort to that omitted Fig, 1,:

retort unit, illustrating .The discharge spout 7 of the blast furnace is referably spaced from the inlet pipe 8 the first unit, so as to permit of the interposition of -a slag settling pot 9,

into which the spout 7 empties, and provided with a. short lip or spout 10 at its several retort units, hereinafter more 8 which may be provl ed face, over which sheet or ribbon-like layer.

4 with a flame openingupper peripheral edge, the said settling pot being suitably mounted on a'wheeled carria e support, whereby it may be readily withdrawn, for dumping and replaced in position. The numera 11 designates generally the cifically described, at their discharge ends with collection hoods 12 communicating through elbows or branch ipes 13 with a main conduit 14 for carry-' of the molten slag, 1n the form of a shallow The top wall 16 is preferably arched.

The front wall is apertured at its-base to I provide a slag outlet 17 discharginginto a refractory pout 18, which in turn empties, through an inlet opening 19 in a side wall of a retort, into the interlor of the next adjacent unit of the series, the inlet opening 19 of the first unit receiving the pipe 8 and the 18 of the last unit discharging to as clearly shown in Fig. 1.

each unit a 20, through which is of great intensity spout waste,

The rear wall of injected a naked flame, and substantial force,

. dered coal or coke, gas or oil, or other form of fuel. For convenient'illustration, I have shown an oil burner 21, its fuel feed pipe being designated at 22 and a pressure air pipe at 23. Additional air, for obvious purposes may between the burner nozzle and flame open- 1 i ng. The top wall of each unit may also .be rovided with an opening 24 for the intro 110- tion of a flux or a reducing agent of any suitable character, when expedient, and these openings may be maintained closed with suitable plugs as desired.

At the forward end of each unit, the top wall 16 is substantially apertured, as at 25,-

or entirely omitted, over which open spaces are mounted the collecting hoods 12, previously referred to, the open bottoms of the hoods preferably projecting slightly beyond the side walls of the units, as indicated at 26 (Fig. 1) to provide substantial air inlets bustion.

preferably intensely heated and under substantial pressure for .and leading from the source flows a continuous stream is providedgenerated from. pow- .base container support. Tinay also be disposedlongitudinally be drawn in through the space.

top side wall surfaces,

to the hoods from the outer atmosphere, for assisting in the oxidation of the volatilized metallic values vaporized off of the shallow stream of the molten slag as it is superheated in passing through the units.

While the various inlets been shown as described, it is obvious that the disposition of these details may be varied in a diflerent arrangement of the several units, so long as the moltenslag is caused to flow. through the superheatin zones in a shallow stream against the sur ace of which and outlets have is directed the hot flames and gases of com To provide for the further addition of 'air,

appearing, I project a twyer nozzle 27, or a series of such nozzles, through either or both side walls of the retorts, to discharge adjacent the bottom walls 15, beneath or into the flowingshallow streamof moltenv slag, which latter'is-indicated at 28. The upper ends of these twyer nozzles '27 -:are connected with a pipe line 29, common to allof them, of compressed air. It is not deemed necessary to illustrate. this source of compressed air nor controlling valves for the twyer nozzles, as the location of such elements are obvious, and these features have also been omitted from theillus- :trativeplan view of. Fig. 1,: as being of obvious disposition As reviously stated," the body of each tort unit 11 is built up of suitable refractory bricks or molded sections, and when assembled the walls are securely tied together by any suitable metallic skeleton frame work, or even a closed metallic sheathing if desired.

In Fig. 2 a preferred arrangement is shown, wherein the bottom of each unit is snuglyseated in a pan or troughelement 30, .of boiler plate or sheet iron or their equivalent, the side walls of which may extend a substantial distance upwardly along the side walls of the unit, providing a substantial Metallic bars 31 and the whole binding structure tied securely together by means of vertical metallic bars 32, appropriately apertured at their ends to receive the crosstie bolt rods 33, extending transversely above the top of the unit and the bottom of the container pan 30.

In Fig. 3, the twyer nozzle 27 is shown as projecting throug that shown in Fig. 2, may obviously enter sides as desired, and other than this, provision is also made in this view for a jacketed chamber 34 to contain a suitable nonconductor of heat, or circulating cooling water.

as the twyer nozzles from either or both purposes hereinafter of the h the side wall opposite to The principlesiof the invention might be well carried out with apparatus other than described, but for the purpose of economy of space and other reasons, the arrangement of a series of unitsat angles to each other has been found peculiarly fitted for the best results.

The actual dimensions of theunits are not' material, within fair limits, and they are suitably mounted at a slight incline from I their inlet ends to their outlet ends, with their discharge'outlets sufiiciently restricted, so that the flow of the molten slag, through the several units after the first one, is the nature of a sluggish; stream or layer',-the' depth of which is comparatively shallow,-

say three inches or less, for it will be recognized the thinner the layer, the morequlckly will it be superheated and volatilized as the" naked flame and hot gases play directly thereon. From the foregoing description it is believed thatthe invention will be fairly ap-- parent, but the functioning of. the apparatus and the steps of the process may be more specifically defined by ment.

' 3A charge of hot molten slag is tapped k from the blast or. other furnace 5 into the slag settling pot 9, through the spout 7 and overflowin into the spout 10, passes through the inlet pipe 8 into the first unit, substanftially fillingthe latter to a line below its burner; -At the same time, the first unit be- 35' gins to empty, through its discharge spout '18, into the next unit, and so on throughout the remainder of the series as set forth.

The amount of-slag drawn from an ordinary blast furnace at each tap is usuallyfromlOOO to 1500 pounds, and each tap is from ten to fifteen minutes apart. From computation, it will take from ten to fifteen minutes, approximately, for the first unit to empty, and a similar amount of time for the slag to flow through each successive unit,

. so that by the time that the blast furnace is ready for another tap, the first unit'will be coming hotter andhotter, and as it ready to receive the charge, without i-nterfering with-the operation of the remaining units.

. As the slag flows from the firstunit, its depth is gradually diminished therein be.-

ows

-- through each successive unit, in a shallow stream, it is superheated to the high state of volatilization by the direct action of the blast of flame thereon, which action also rifiies its surface to agitate the mass and present a constantly changing surface'to the direct action of the flame and heated gases. The flowing -slag is also agitated to a minor degree in its passage from unit to unit.

This treatment, of causing the blast flame and hot gases to directly impinge upon the surface of a layer of slow flowing slag, has

the following state-.

within the purview of, the" ensuin and a reasonable construction of-t ejscope' thereof contemplating a fair range of equiv alone been found sufiicient to so highly superheat the slag as to.read1ly extract the z 1nc' vaporstherefrom, but naturally the addltlon of a flux such as limestone, or a reducing agent such as coke, greatly facilitates and accelerates the action. Y p The zinc vapors arising are then substan tiallyv aerated by the incoming I fresh air through the spaced openings 26, causing them to become rapidl oxidized, whereupon.

they are conveyed o to the filter bags-or other collection I receptacles, not shown,

, through the hoods and connections with the main conduit 14-,through which a suctional force may be created by any suitable means not necessary to illustrate.

-Where the shallow stream of sla is constantly' agitated to present a continuously changing new surface, it is manifest that the intense flame and hot gases playing thereon is caused to more intimately contact with the molecular particles throughout the mass,

atan extremely high'temperature to' vapor ize its zinc values. I While I have thus fully disclosed my'imroved method and an apparatus successullycarrying out, thesteps thereof, it will be understood thatI do not limit-myself to the exact details set forth, excepting as come alents.

claims- 11o- What I do claim as newahd patentable 1. The-method of recovering volatile me tallic values from molten slag, whichin g.

eludes the steps of causing the molten slag, containing a suitable reduclng agent, to flow,

in a comparatively shallow layer, through an inclosed superheating zone; directin' a hot-{12o gases, into positive intimate contact with the shallow layer of flowing slag, to cause the sufliciently intense naked flame and its vaporization of the metallic values to be recovered; oxidizing the metallic vapors arising therefrom; and finally collecting the oxidized vapors in the form of metallic oxids, substantially as described. I

' 2. The method of recoveringlvolatile metallicvalues from molten slag, which includes the steps of causing the molten slag,

from; and finally collecting the oxidized vapors in the form of metallic oxids, substantially as described.

3. The method of recovering volatile metallic values from molten slag, which iiicludes the steps of causing the molten slag,

containing a suitable reducing agent, to flow. in a comparatively shallow layer, through an inclosed superheating zone; forcing air through said flowin slag to agitate the same; directing a su ciently intense naked flame and its hot gases, into positive contact substantially with the molecular particles of said shallow layer of agitated flowing slag, to cause the vaporization of the metallic values to be recovered; oxidizing the metallic vapors arising therefrom; and-finally collecting the oxidized vapors in the'form of metallic oxids, substantially as described.

4. The method of recovering volatile metallic values from molten slag, which includes. the steps of causing the molten slag, containing a suitable flux and reducing agent, to flow, in comparatively shallow layers, through a series of substantially closed communicating superheating retorts; causing the vaporization of the metallic values to,be recovered by directing sufiiciently intense blasts'of naked flames andvtheir hot gases into positive contact with the shallow 40 layers of flowing slag; oxidizing the metallic vapors arising therefrom; and finally collecting the oxidized vapors in the form of metallic oXids from each superheated retort unit, substantially as described.

Y tallic values from molten slag, an elpngated substantially closed superheating retort,

having an inlet and an outlet for the molten slag and an outlet for oxidized vapors therefrom, and said retort being mounted and functioning to continuously flow a suitable charge of the molten slag therethrough in a comparatively shallow layer, in combination with means for directing a sufficiently intense, blast of naked flame and its hotgases, into,positive intimate contact with said flowing shallow layer of slag, to cause the vaporization of its metallic values to be recovered; means providing for the aeration. of the metallic vapors, arising from said superheated slag, to oxidize the same; and means in communication with said oxidized vapor outlet for collecting the resulting oxidized vapors in the form of metallic oxids, substantially as described. 7

5. In apparatus for recovering volatile me 6. In apparatus for recovering volatile metallic values from molten slag, an elongated substantially closed superheating retort, having an inlet and an outlet for the molten slag and an outlet for metallic vapors arising therefrom and adapted to be oxidized, said retort being mounted and functioning to continuously flow a suitable charge of the molten slag therethrough in a comparativel shallow layer, in combination with means for injecting air currents through the body of said flowing shallow layer of slag to thoroughly agitate the same; means for applying heat to said agitated flowing shallow layer of slag of sufficient intensity to vaporize off its metallic values to be recovered; and means, in communication with said oxidized vapor outlet, for collecting theresulting metallic vapors in the form of metallic oxids, substantially as described.

7. In apparatus for recovering volatile metallic values from molten slag, the combination of a series of suitable elongated communicating superheating retort units, each having a slag inlet and outlet, and mounted and functioning to flow a suitable charge of the molten slag therethrough in' comparatively shallow layers; a feed unit for said series adapted to receive a charge of the molten slag; flame openings through said units, disposed above the flow of slag therein; means for directing sufliciently intense blasts of naked flame and hot gases, through said flame openings into positive contact with the flowing shallow layers of slag, to cause the vaporization of the metallic values to be recovered; means providing for the aeration of the metallic vapors arising from said superheated flowing slag, to oxidize said vapors; an outlet for said recovered values; and means, in communication with said last named outlet, for collecting said oxidizedvapors in. the form of metallic oxids, substantially as described.

8: In apparatus for recovering volatilemetallic values from molten slag, the combination of a communicating series of suitable retort units, each having a slag inlet and outlet, and mounted and functioning to flow a suitable charge of the molten slag'therethrough in comparatively shallow layers; a feed unit for said series adapted to receive-a charge of y the molten slag; twyer nozzles, communicating with a source of compressed air, and discharging into said units below the line of flow of slag. therein, for agitating said flowing slag; flame openmgs through said units,-

disposed above the flow of slag therein;'

means blasts of naked flame, though said flame openings into positive contact with the flow ingishallow agitated layers of slag, to cause the vaporization of the metallic values to be recovered, said arising metallic vapors being oxidized by aeration; an outlet for the for directing sufficiently intense '125 recovered oxidized values; and means in communication with said last named outlet -for collecting said recovered values in the "form of metallic oxids, substantially as de tioning substantially as described to cause a suitable charge of the molten slag 'to flow therethrough in comparatively shallow layers; burner openings discharging into said units above saidfiowing shallow layers of lag; burners for said openings, function-- ing as described; an outlet in each of said units for the exit of the vapors arising from the superheated slag; hoods covering said outlets and providing openings 'for the admission of air to said metallic vapors to oxidize same; branch pipes leading from said hoods; and a suitable conduit, common to all of said branch pipes, for conveying off said oxidized vapors in the form of metallic oxids, substantially as described.

In testimony whereof, I aflix my signature.-

1 HERMAN WITTEBORG. 

